Multiple choice general knowledge math & puzzles

What is the result of - Lt tan x x->pi/2

  1. infinity

  2. 0

  3. 1

  4. invalid limit
Reveal answer Fill a bubble to check yourself
D Correct answer
AI explanation

tan(x) = sin(x)/cos(x), and cos(x) crosses zero at x = pi/2, so tan(x) blows up there. Approaching from the left it goes to +infinity, but approaching from the right it goes to -infinity — since the one-sided limits disagree, the two-sided limit simply does not exist, making it an invalid/undefined limit rather than a single value like +infinity.

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